Is it safe for young children to sit around in wet clothing?!

Is it safe for young children to sit around in wet clothing?

We have had a lot of wet weather here lately and today my daughter-in-law called in with my grandsons (aged eight,seven and three) having been caught in a shower.The boys' clothing was damp (she hadn't put them in proper waterproofs) and when it started to bucket down she had to stay here (even though she was only planning on a brief visit).The boys were shivering (although she denied this later) and I suggested getting them changed into the clothes that I have for the older two here for when they change after school (which she says are "old-fashioned" but my grandsons love them so I don't know if that had anything to do with it).
She refused and just told me to "turn the heating up"!
Is it dangerous for children to wear wet clothing?
I am very concerned as it may affect their bones and lead to arthritis in later life.
When my own boys got soaked I stripped them and put them into a hot bath and then wrapped them up warmly even in Summer.
Is she being irresponsible?

Ask her how she would like to sit around in wet clothes. And why should you turn the heat up and raise your bills to accommodate her selfishness?

So what if the clothes are "old-fashioned"? That doesn't matter when someone is wet and cold. They could have changed into the dry clothes and she could have thrown their other clothes in the dryer to dry for them to wear home if she was so vain about what you had.

This is child abuse and someone needs to knock some sense into her head so she won't think of herself all the time. The comfort of the kids should always be a high priority for any parent.

Wearing wet clothes won't contribute to arthritis, that is something that will happen depending on their family history, weight and lifestyles as they grow up. They could get colds and/or pneumonia from this, though.

But heaven forbid if the boys comfort comes before her vanity.